Many people believe that installing more stop signs, particularly at all approaches to intersections, will slow traffic speeds and prevent crashes.

There is no real evidence to indicate that stop signs decrease the speed of traffic. Impatient drivers view the additional delay caused by unwarranted stop signs as "lost time" to be made up by driving at higher speeds between stop signs.

Unwarranted stop signs breed disrespect by motorists who tend to ignore them or slow down without stopping. These "roll through" stops can sometimes lead to tragic consequences.

The Massachusetts Highway Department requires that all cities and towns follow the national guidelines outlined in the "Manual on Uniform Traffic Control Devices" (MUTCD) in determining the use of traffic control devices, including STOP signs:

The purpose of the stop sign is to prevent collisions. It is not intended, nor shall it be used for the control of speed, traffic calming, or to forestall pedestrian, rear-end, or turning movement accidents.

To insure uniformity in stop sign studies and recommendations, the warrants as provided in the 2003 MUTCD. Section 2B.05 will govern.

Multi-way stop Signs must meet the warrant criteria as outlined in Section 2B.07 of the 2003 MUTCD.

Source: Massachusetts amendments to the 2003 manual on uniform traffic control devices and the standard municipal traffic code, October 2006

Stop signs are designed to assign and control the right-of-way at locations where the prevailing traffic volumes and reported crash history make assignment of right-of-way desirable. As simple as that may appear on the surface, the decision to install these signs requires careful consideration of engineering criteria.

To determine whether or not a stop sign would be the best and most appropriate measure of traffic control, Northampton Department of Public Works (DPW) engineers analyze the various characteristic of an intersection. Some of the questions they ask themselves include:

Is this an intersection of a minor road with a main road where application of the normal right-of-way rule (e.g. yield to the right) is unduly hazardous?

Is this an intersection where a street enters an arterial (major) street?

Is this an intersection where a combination of speed, restricted view and reported crash history indicates a need for control by the stop sign?

In order for Northampton to consider the installation of an all-way stop, MassHighway requires that the following MUTCD "warrants" must be satisfied:

Where traffic control signals are justified, the multiway stop is an interim measure that can be installed quickly to control traffic while arrangements are being made for the installation of the traffic control signal.

A crash problem, as indicated by 5 or more reported crashes in a 12-month period that are susceptible to correction by a multiway stop installation. Such crashes include right- and left-turn collisions as well as right-angle collisions.

Minimum volumes:The vehicular volume entering the intersection from the major street approaches (total of both approaches) averages at least 300 vehicles per hour for any 8 hours of an average day, and

The combined vehicular, pedestrian, and bicycle volume entering the intersection from the minor street approaches (total of both approaches) averages at least 200 units per hour for the same 8 hours, with an average delay to minor-street vehicular traffic of at least 30 seconds per vehicle during the highest hour, but

The Department of Public Works (DPW) analyze problematic intersections using using historical crash data maintained by the Northampton Police Department together with volume and speed data collected through traffic study.

Sometimes these traffic studies are conducted for the city by an outside entity like the Pioneer Valley Planning Commission (PVPC) or, in the case of a new commercial or housing project, by private engineering firms paid for by the project developer.

The Massachusetts DMV driver’s manual offers the following guidance: “If a four way or all-way sign is added to a STOP sign at an intersection, all traffic approaching the intersection must stop. The first vehicle in the intersection or four-way stop has the right of way.”

The unofficial rules of thumb at four-way stop intersections are as follows:

If you are the only vehicle at the intersection, stop, look all ways, and proceed.

If there is already another vehicle at the intersection, it has the right-of-way.

If two vehicles arrive at the same time, the vehicle on the right has the right-of way.

When misused, the stop sign can create an inconvenient, and even dangerous, situation for motorists and pedestrians. Drivers are more likely to intentionally violate unwarranted signs.

Research has shown that unwarranted stop signs and stop signs that have been used for speed control, do not have the effect desired. Speeds between the stop signs increase as drivers try to make up for lost time. Drivers tend to roll through the unwarranted stop signs with higher frequency (over 50%).

Traffic accidents at unwarranted stop controlled intersection are often higher than when the intersection was uncontrolled or two-way stop controlled. There is also an increase in noise and air pollution levels to nearby residents as the result of vehicles braking and accelerating.

Stop signs cannot be viewed as a cure-all for solving all safety problems, but, when properly located, they can be useful traffic control devices to enhance safety for all roadway users.